Secondary glazings, for example storm windows, are often installed with prepositioned primary glazings in order to provide improved thermal insulation. In many instances it is desirable to combine the two glazings with a venetian blind assembly. Conventionally this is done by positioning the blind assembly in the interior of a building structure interiorly of the two glazings. The blind assembly in such instances is then subjected to accumulation of dirt and dust existing in the building.
Venetian blind assemblies have been positioned between two glazings where they are sealed from dust and dirt and where special means have been provided to tilt the slats of the blind assembly. Such constructions including two glazings having a venetian blind therebetween are usually factory assembled as a single unit in a single frame with the unit then being installed in a building. While this procedure is practical with buildings under construction, it is impractical in completed buildings having preinstalled primary glazings as the primary glazings must be ripped out in order to allow installation of the double glazing units.
A problem exists in simply positioning a venetian blind assembly next to a primary glazing and then installing a secondary glaZing or storm window next to the blind assembly. In order to provide means to tilt the slat of the blind assembly, the primary glazing or primary frame must be altered such as drilling holes or the like in the frame in order to run a tilting mechanism therethrough so that it can be accessible to an operator. Such alterations add further to the expense of installation.
Further existing prepositioned primary glazings may be preinstalled in an existing building structure in a number of different ways. For example the primary glazing may be included in a casement-type window, may involve a single or double hung sash or may involve thick wall openings such that it would be easier or more practical to install the secondary frame or storm window on the interior side of the building structure rather than, as in the more common practice, on the exterior side of a building structure. Consequently, many different configurations of secondary frames are required in order that secondary glazings may be installed with the various forms of primary glazings as outlined above, and some sort of provision has to be made in each instance to provide a means for tilting the slats of a blind assembly positioned between the two glazings.
It is therefore an object of my invention to provide for a unitized secondary glazing frame and venetian blind assembly which may be installed as a unit with a pre-existing prepositioned primary glazing and which may be installed either on the exterior or interior sides of a building structure.
It is a further object of the invention to provide for a unitized secondary glazing frame and venetian blind assembly which may be readily installed with a vertical or horizontal sliding sash, a fixed sash or a pivoting sash.
It is a further object of the invention to provide for a unitized secondary frame and venetian blind assembly which may be installed in building structures where the spacing between the blind assembly and primary glazing means may differ in several constructions and which can be accommodated by a single common unitized frame and venetian blind assembly.
It is a still further object of the invention to provide for a unitized secondary glazing frame which may be installed with existing prepositioned primary glazings and to provide for a convenient reliable means for tilting the slats of the blind assembly without altering construction of the primary frame and primary glazing.